CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

52/944 (6%) adverse birth outcomes, occurring in 9/93 (10%) TP-PA positive PHIV (including 5/93 [5%] stillbirths), 20/385 (5%) of TP-PA negative PHIV, 2/24 (8%) of TP-PA positive people without HIV, and 21/442 (5%) of TP-PA and HIV negative people (P=0.26). Of 54 PHIV with RPR titers available, 8 (15%) were non-reactive, 38 (70%) were <1:32 and 8 (15%) were ≥1:32. In multivariable analysis, gestational age and attending ≥4 antenatal care visits were independently associated with the composite adverse birth outcome, but maternal TP-PA seropositivity and HIV infection were not (Table). An HIV × TP-PA product term was not statistically significant. Conclusion: Maternal HIV or TP-PA seropositivity did not increase the risk of adverse birth outcomes, though stillbirth incidence among TP-PA positive PHIV was higher than prior studies from sSA. High TP-PA seroprevalence and RPR positivity among PHIV emphasize the need to improve prenatal care for PHIV with enhanced syphilis screening and treatment.

and combined endpoints of any adverse or severe adverse outcome. We also evaluated low (<50kg) and high (≥80kg) early pregnancy weight (before 24 weeks) and hypertension in pregnancy (SBP≥140 or DBP≥90 mm/Hg). Results: Of 4,265 eligible individuals (median [IQR] age in pregnancy: 36 [32, 39] years), 1,102 (26%) switched from NVP to DTG and 3,163 (74%) did not switch from NVP prior to pregnancy. The most common backbones during pregnancy were TDF/3TC (90%) and TDF/FTC (8%) for switchers and ZDV/3TC (60%) and TDF/FTC (39%) for non-switchers. Comparing switchers with non-switchers, RRs (95% CIs) were 0.82 (0.75, 0.89) for any adverse and 0.84 (0.71, 1.00) for any severe adverse outcome. These differences were driven by SGA and very SGA (Figure, Left Panel). Switchers were less likely to have low and more likely to have high early pregnancy weight (Figure, Right Panel); the adjusted mean difference (95% CI) in early pregnancy weight was 2.9 (1.8, 4.1) kg. While switchers became pregnant in later years, sensitivity analyses indicated little evidence for time-trends in birth outcomes over the study period. Results were similar when excluding ZDV backbones. Conclusion: Switching from legacy NVP-based regimens to DTG/TDF/XTC prior to pregnancy may reduce the risk of low maternal weight in early pregnancy and fetal growth restriction. This study provides further evidence that specific regimens impact birth outcomes, and that switching from legacy regimens prior to conception can improve birth outcomes.

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Maternal and Pregnancy Outcomes in Women Initiating and Declining PrEP in Pregnancy: IMPAACT 2009 Benjamin H Chi 1 , Deborah Kacanek 2 , Emily Brown 3 , K. Rivet Amico 4 , Sharon Huang 2 , Teacler Nematadzira 5 , Elizea Horne 6 , Clemensia Nakabiito 7 , Sharon K. Mambiya 8 , Violet Korutaro 9 , Benjamin Johnston 10 , James F. Rooney 11 , Lynda Stranix-Chibanda 5 , for the IMPAACT 2009 Study Team 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 2 Harvard TH Chan School of Public Health, Boston, MA, USA, 3 FHI 360 , Lusaka, Zambia, 4 University of Michigan, Ann Arbor, MI, USA, 5 University of Zimbabwe, Harare, Zimbabwe, 6 Wits Reproductive Health and HIV Institute, Johannesburg, South Africa, 7 Makerere University–Johns Hopkins University Research Collaboration, Kampala, Uganda, 8 Malawi College of Medicine-Johns Hopkins University Research Project, Blantyre, Malawi, 9 Baylor College of Medicine Children's Foundation, Kampala, Uganda, 10 Frontier Science & Technology Research Foundation, Inc, Amherst, NY, USA, 11 Gilead Sciences, Inc, Foster City, CA, USA Background: FTC-TDF-based PrEP is recommended for pregnant people in settings of high HIV transmission. However, few have evaluated uptake, maternal safety, and pregnancy outcomes in the context of a clinical trial. Methods: The PrEP Comparison Component of IMPAACT 2009 enrolled pregnant participants aged 16-24 years at <32 weeks gestation in Malawi, South Africa, Uganda, and Zimbabwe. Participants were enrolled in parallel cohorts based on choice to initiate or decline daily oral FTC-TDF for PrEP at entry. All were followed in pregnancy to 6 months postpartum and could start or stop PrEP at any time. While on PrEP, they received Integrated Next Step Counseling, regular drug level feedback via TFV-DP from dried blood spots, and weekly two-way text messaging. Adverse events (AEs) were graded per DAIDS toxicity tables and assessed for relatedness to PrEP. Proportions (with Clopper-Pearson 95% confidence intervals) were calculated for highest-grade AEs through pregnancy outcome by PrEP use. Adverse pregnancy outcomes included fetal loss, preterm birth, and small-for-gestational-age by INTERGROWTH-21st standards. Results: From March to December 2022, 350 eligible participants enrolled (mean age: 21 years; median gestational age: 24 weeks). Among 335 participants with pregnancy outcome information, 233 initiated PrEP in pregnancy (229 at enrollment, 4 later). Another 117 declined at entry and never initiated PrEP during pregnancy. Median duration of antenatal PrEP use was 11 weeks (IQR: 7.7-15). A total of 31 (9%) participants experienced at least one grade ≥3 AE through delivery, with a greater proportion among PrEP initiators (11.2%, 95%CI: 7.4-15.9%) vs. decliners (4.3%, 95%CI:1.4-9.7%). Most frequent grade ≥3 AEs were complications of pregnancy or delivery (9% for initiators vs. 3% for decliners). None were considered related to PrEP use. No participants acquired HIV infections during follow-up. Among those with delivery information, median gestational age was 39.4 weeks (IQR: 38.4-40.4) and median infant birthweight 3095g (IQR: 2800-3350). 79 (24%) participants reported adverse pregnancy outcomes, with no differences between the two groups (table). Conclusion: Our findings further support the safety of FTC-TDF in pregnancy. Despite the high occurrence of AEs, none appeared related to PrEP use. While other PrEP modalities undergo evaluation for antenatal populations, daily oral FTC-TDF remains a safe and essential component of HIV prevention in pregnancy.

Poster Abstracts

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HIV and Syphilis Coinfection in Pregnancy and Adverse Birth Outcomes in Uganda Timothy Kintu 1 , Mehal Churiwal 2 , Onesmus Byamukama 1 , Ingrid V. Bassett 3 , Mark J. Siedner 3 , Anacret Byamukama 4 , Edna Tindimwebwa 4 , Julian Adong 1 , Elias Kumbakumba 1 , Stephen Asiimwe 4 , Joseph Ngonzi 1 , Lisa M. Bebell 3 1 Mbarara University of Science and Technology, Mbarara, Uganda, 2 Columbia University, New York, NY, USA, 3 Massachusetts General Hospital, Boston, MA, USA, 4 Kabwohe Clinical Research Center, Kabwohe, Uganda Background: The incidence of syphilis is increasing worldwide. Little is known about the combined impact of maternal HIV and syphilis coinfection on birth outcomes, especially in sub-Saharan Africa (sSA), where HIV prevalence is high. Methods: We analyzed data from two prospective birth cohorts enrolled in southwestern Uganda from 2017 – 2023. All PHIV reported taking antiretroviral therapy (ART). Participants were tested for syphilis using a Treponema pallidum particle agglutination (TP-PA) rapid test on peripheral blood (positive test indicates treponemal exposure but cannot distinguish current vs prior infection). In one cohort, we also tested umbilical cord blood for and performed rapid plasma reagin (RPR) testing for TP-PA positive blood samples. Our primary outcome was a composite adverse birth outcome, including low birthweight (<2.5kg), stillbirth, neonatal death within 14 days of birth, or 5-minute APGAR<7. We compared outcomes by HIV and TP-PA seropositivity using chi square tests and fitted multivariable logistic regression models to determine adjusted associations between maternal HIV and syphilis infection and birth outcomes. Results: Of 944 women, 93 were TP-PA positive PHIV, 385 were TP-PA negative PHIV, 24 were TP-PA positive people without HIV and 442 were TP-PA negative people without HIV. Mean age of TP-PA positive PHIV was 28±6 years, 60/93 (65%) initiated ART before conception, and 13% had detectable HIV viremia. Of 117 (12%) TP-PA positive people, 93 (79%) were PHIV (P<0.001). There were

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